Kdenlive/Manual/Effects/Alpha manipulation/Alpha operations: Difference between revisions

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== Alpha operations ==
== Alpha operations ==


This is Frei0r [http://www.mltframework.org/bin/view/MLT/FilterFrei0r-alpha0ps alpha0ps] - Display and manipulation of the alpha channel <br>
This is Frei0r [http://www.mltframework.org/bin/view/MLT/FilterFrei0r-alpha0ps alpha0ps] - Display and manipulation of the alpha channel.


Use this to shrink, grow, threshold and visualize the alpha channel.
Use this to shrink, grow, threshold and visualize the alpha channel.


From the [http://www.piksel.no/trac/browser/src/filter/alpha0ps/readme Frei0r-alpha0p readme] file:<br>
From the [http://www.piksel.no/trac/browser/src/filter/alpha0ps/readme Frei0r-alpha0p readme] file:


This plugin can shrink, grow, threshold and invert the alpha channel. It is mainly intended to improve keying edges.
This plugin can shrink, grow, threshold and invert the alpha channel. It is mainly intended to improve keying edges.
It can also display the alpha channel in various ways, to enable quick assessment of the effect.
It can also display the alpha channel in various ways, to enable quick assessment of the effect.
It is cascadable, so for example one can do a soft shrink first and then threshold, which gives a slightly different result than a hard shrink.
It is cascadable, so for example one can do a soft shrink first and then threshold, which gives a slightly different result than a hard shrink.


''Parameters:''<br>
'''Parameters:'''
 
''Display:''<br>
what to display. Choices are seven: Image, Alpha as gray, Gray+red, Selection on black, Selection on gray, Selection on white and Selection on checkers.
 
This is intended for monitoring during adjustment mostly. After adjusting the parameters, it should be left on "Image", which lets the unchanged input image through - this plugin is intended to change only the alpha channel...
 
''Display input alpha:''<br>
use input alpha for the display function above. (Check what alpha we are getting on the input)
 
'''Operation:''<br>
select the operation to be done on the alpha channel. Currently there are six choices: NO OP, Shave, Shrink hard, Shrink soft, Grow
hard, Grow soft, Threshold.
 
"Shave" try to remove the "hairy" stuff, and also shrinks the selection a bit.<br>
 
The "hard" operations introduce no new values to the alpha channel, so if you have a "hard" key (only 0 and 255) it will stay that way.
The "soft" operations will introduce interpolated values, making the edge softer.
NOTE: the shave, shrink and grow operations are quite slow, because they do many conditional operations on each pixel.


''Threshold:''<br>
;'''Display:'''
this is only used for the Threshold operation.
:what to display. There are seven options: <menuchoice>Image</menuchoice>, <menuchoice>Alpha as gray</menuchoice>, <menuchoice>Gray+red</menuchoice>, <menuchoice>Selection on black</menuchoice>, <menuchoice>Selection on gray</menuchoice>, <menuchoice>Selection on white</menuchoice> and <menuchoice>Selection on checkers</menuchoice>.<br /><br />This is intended for monitoring during adjustment mostly. After adjusting the parameters, it should be left on <menuchoice>Image</menuchoice>, which lets the unchanged input image through - this plugin is intended to change only the alpha channel...


''Shrink/grow amount:''<br>
;'''Display input alpha:'''
how far the shrinking/growing will extend.
:use input alpha for the display function above. (Check what alpha we are getting on the input)


''Invert:''<br>
;'''Operation:'''
Inverts the input alpha channel, transparent will become opaque and vice versa.
:select the operation to be done on the alpha channel. Currently there are six choices: <menuchoice>NO OP</menuchoice>, <menuchoice>Shave</menuchoice>, <menuchoice>Shrink hard</menuchoice>, <menuchoice>Shrink soft</menuchoice>, <menuchoice>Grow hard</menuchoice>, <menuchoice>Grow soft</menuchoice>, <menuchoice>Threshold</menuchoice>.


[[File:Alpha operations.png]]
<menuchoice>Shave</menuchoice> try to remove the "hairy" stuff, and also shrinks the selection a bit.


<br\>
The ''hard'' operations introduce no new values to the alpha channel, so if you have a "hard" key (only 0 and 255) it will stay that way.
[[File:alpha_operations_display_menu.png]]


Display Menu Options
The ''soft'' operations will introduce interpolated values, making the edge softer.


<br\>
{{Note|The shave, shrink and grow operations are quite slow, because they do many conditional operations on each pixel.}}
[[File:Alpha operations operation menu.png]]


Operation Menu Options
;'''Threshold:'''
:This is only used for the Threshold operation.


<br\>
;'''Shrink/grow amount:'''
:How far the shrinking/growing will extend.


;'''Invert:'''
:Inverts the input alpha channel, transparent will become opaque and vice versa.


{|
|[[File:Alpha operations.png]]
|[[File:alpha_operations_display_menu.png|thumb|Display Menu Options]]
|[[File:Alpha operations operation menu.png|thumb|Operation Menu Options]]
|}


=== Tutorial 1 ===
=== Tutorial 1 ===


Shows usage of alpha operations - shrinkhard as well as the following effects:  [[Special:MyLanguage/Kdenlive/Manual/Effects/Alpha_manipulation/Blue_Screen|blue screen]], [[Special:MyLanguage/Kdenlive/Manual/Effects/Enhancement/Denoiser|denoiser]]  and [[Kdenlive/Manual/Effects/Misc/keysplillm0pup|keysplillm0pup]]  
Shows usage of alpha operations - <menuchoice>Shrink hard</menuchoice> as well as the following effects:  [[Special:MyLanguage/Kdenlive/Manual/Effects/Alpha_manipulation/Blue_Screen|blue screen]], [[Special:MyLanguage/Kdenlive/Manual/Effects/Enhancement/Denoiser|denoiser]]  and [[Kdenlive/Manual/Effects/Misc/keysplillm0pup|keysplillm0pup]]  
{{#ev:youtube|l43Hz7YEcYU}}
{{#ev:youtube|l43Hz7YEcYU}}
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[[Category:Kdenlive]]
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Revision as of 12:08, 6 November 2012

Other languages:

<tarnslate>

Alpha operations

This is Frei0r alpha0ps - Display and manipulation of the alpha channel.

Use this to shrink, grow, threshold and visualize the alpha channel.

From the Frei0r-alpha0p readme file:

This plugin can shrink, grow, threshold and invert the alpha channel. It is mainly intended to improve keying edges. It can also display the alpha channel in various ways, to enable quick assessment of the effect.

It is cascadable, so for example one can do a soft shrink first and then threshold, which gives a slightly different result than a hard shrink.

Parameters:

Display:
what to display. There are seven options: Image, Alpha as gray, Gray+red, Selection on black, Selection on gray, Selection on white and Selection on checkers.

This is intended for monitoring during adjustment mostly. After adjusting the parameters, it should be left on Image, which lets the unchanged input image through - this plugin is intended to change only the alpha channel...
Display input alpha:
use input alpha for the display function above. (Check what alpha we are getting on the input)
Operation:
select the operation to be done on the alpha channel. Currently there are six choices: NO OP, Shave, Shrink hard, Shrink soft, Grow hard, Grow soft, Threshold.

Shave try to remove the "hairy" stuff, and also shrinks the selection a bit.

The hard operations introduce no new values to the alpha channel, so if you have a "hard" key (only 0 and 255) it will stay that way.

The soft operations will introduce interpolated values, making the edge softer.

Note
The shave, shrink and grow operations are quite slow, because they do many conditional operations on each pixel.


Threshold:
This is only used for the Threshold operation.
Shrink/grow amount:
How far the shrinking/growing will extend.
Invert:
Inverts the input alpha channel, transparent will become opaque and vice versa.
Display Menu Options
Operation Menu Options

Tutorial 1

Shows usage of alpha operations - Shrink hard as well as the following effects: blue screen, denoiser and keysplillm0pup {{#ev:youtube|l43Hz7YEcYU}}

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